This invention relates to rear discharge mowers and mulching mechanisms.
It is known to provide a mower deck with a plurality of blade spindles which support and drive mower blades within a mower housing The mower deck is coupled to a vehicle such as a tractor for driving the spindles and blades. It is known to position the deck beneath the belly of the tractor, and between the fore and aft pairs of tractor wheels. A discharge outlet is often formed in the rear portion of the deck for allowing the grass clippings to exit the deck and be deposited on the ground between the tractor's wheels. The various blade spindles are often coupled together by a series of belts and pulleys. The blades are often adapted to rotate in the same direction, thereby simplifying the belt and pulley arrangement, and eliminating the need for a complicated idler mechanism. Many conventional rear discharge mowers do not adequately disperse the clippings on the ground, but rather form unsightly windrows of grass clippings. It would therefore be desirable to provide an improved rear discharge mower.
It is often desirable to mulch the vegetation clippings while they remain within the mower deck, such that the size of the discharged clippings is reduced. The smaller clippings are then less noticeable in a lawn, and more readily decompose to provide nutrients to the underlying grass. Many conventional mulching mechanisms have been devised which completely block the discharge of clippings from the mower deck in an attempt to keep the clippings in an area where they can be re-cut by the blade. However, blocking the discharge outlet also acts to reduce the flow of air from the mower deck such that the vacuum effect created by the blades may be undesirably reduced, thereby reducing the quality of cut. Many mulching mowers tend to hold or suspend a large volume of clippings within the deck. When such a mower is stopped during grass mowing operations, such as for reversing the direction of travel when mowing in tight quarters, an undesirable amount of suspended clippings may fall from the deck to the ground in unsightly clumps. Furthermore, many conventional mulching mechanisms do not allow the mower to be readily switched back and forth between the mulching mode and the normal cutting mode. It would be desirable to provide an improved mulching apparatus, and particularly one suited for use with a rear discharge mower.
It is known to provide a plurality of cutting edges within a mower housing and rotatable about the same spindle such that the additional blade or blades function to re-cut or mulch the clippings within the housing. A first type of multiple blade mechanism provides various cutting blades which are formed from a single metal part, which can be a relatively costly to manufacture A second type of multiple cutting edge mechanism provides a plurality of separate cutting blades each coupled with the spindle. The primary cutting blade must be relatively sturdy and is typically made of a thick metal to thereby withstand impacts with rocks and other obstructions during mowing operations. The other blades which act to mulch or re-cut the clippings can be formed from a thinner, lighter material, since impacts with heavy obstructions are less likely. Since the blades are separate parts, the different blades can readily be formed having different thicknesses, thereby reducing the cost and the combined weight of the blades. Reducing the combined weight of the blades helps reduce wear on other mower components, such as a blade brake or clutch. The blades are either welded together or have separate mechanisms for securing the blades for rotation with the spindle. The welding or separate attachment process typically adds expense to the manufacture and assembly of the mower. It would therefore be desirable to provide a mechanism for coupling a plurality of mower blades for rotation together in an effective, cost efficient manner.